U.S. patent application number 11/553029 was filed with the patent office on 2007-03-08 for coil antenna structure and portable electronic apparatus.
This patent application is currently assigned to MURATA MANUFACTURING CO., LTD.. Invention is credited to Gaku KAMITANI, Kazunari KAWAHATA, Takehiro KONOIKE, Hiroshi MARUSAWA.
Application Number | 20070052600 11/553029 |
Document ID | / |
Family ID | 37532271 |
Filed Date | 2007-03-08 |
United States Patent
Application |
20070052600 |
Kind Code |
A1 |
KAMITANI; Gaku ; et
al. |
March 8, 2007 |
COIL ANTENNA STRUCTURE AND PORTABLE ELECTRONIC APPARATUS
Abstract
A coil antenna structure includes a first magnetic component
extending in the thickness direction of a tabular primary casing. A
second magnetic component and a third magnetic component, which are
magnetically connected to the first magnetic component, are
disposed on the first principal surface side and the second
principal surface side of the primary casing, respectively. The
first magnetic component is provided with a coil component
surrounding it. In this manner, a U-shaped magnetic path is
provided at an end portion of the primary casing so as to detour
around a substrate defining an internal conductor. Likewise, a
U-shaped magnetic path including fourth to sixth magnetic
components is provided in a secondary casing defining a clamshell
type casing together with the primary casing so as to detour around
a substrate defining as an internal conductor.
Inventors: |
KAMITANI; Gaku;
(Nagaokakyo-shi, Kyoto-fu, JP) ; MARUSAWA; Hiroshi;
(Nagaokakyo-shi, Kyoto-fu, JP) ; KONOIKE; Takehiro;
(Nagaokakyo-shi, Kyoto-fu, JP) ; KAWAHATA; Kazunari;
(Nagaokakyo-shi, Kyoto-fu, JP) |
Correspondence
Address: |
MURATA MANUFACTURING COMPANY, LTD.;C/O KEATING & BENNETT, LLP
8180 GREENSBORO DRIVE
SUITE 850
MCLEAN
VA
22102
US
|
Assignee: |
MURATA MANUFACTURING CO.,
LTD.
10-1 Higashikotari 1-chome
Nagaokakyo-shi
JP
617-8555
|
Family ID: |
37532271 |
Appl. No.: |
11/553029 |
Filed: |
October 26, 2006 |
Current U.S.
Class: |
343/702 ;
343/787; 343/788 |
Current CPC
Class: |
G06K 7/10316 20130101;
H01Q 1/243 20130101; G06K 7/10326 20130101; G06K 7/0008 20130101;
G06K 19/0723 20130101; H01Q 7/08 20130101 |
Class at
Publication: |
343/702 ;
343/787; 343/788 |
International
Class: |
H01Q 1/24 20060101
H01Q001/24 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 14, 2005 |
JP |
2005-174099 |
Aug 26, 2005 |
JP |
2005-245541 |
Oct 12, 2005 |
JP |
2005-297223 |
Claims
1. A coil antenna structure comprising: a tabular casing having a
first principal surface and a second principal surface opposed
thereto; and a magnetic component and a coil component surrounding
the magnetic component provided in the casing; wherein the magnetic
component extends at least in a thickness direction of the casing
and defines a magnetic path from the first principal surface side
to the second principal surface side.
2. The coil antenna structure according to claim 1, wherein the
magnetic component defines a first magnetic component, and a second
magnetic component magnetically connected to the first magnetic
component is disposed on the first principal surface side of the
casing.
3. The coil antenna structure according to claim 2, wherein a third
magnetic component magnetically connected to the first magnetic
component is disposed on the second principal surface side of the
casing.
4. The coil antenna structure according to claim 3, wherein the
first, the second, and the third magnetic components comprise an
integral magnetic component.
5. The coil antenna structure according to claim 4, wherein the
integral magnetic component is a sheet-shaped magnetic component
that is bent over the first principal surface and the second
principal surface of the casing.
6. The coil antenna structure according to claim 3, wherein a
plurality of groups, each comprising the first, the second, and the
third magnetic components, are provided.
7. The coil antenna structure according to claim 3, wherein at
least one of the second magnetic component and the third magnetic
component is provided separately from the first magnetic
component.
8. The coil antenna structure according to claim 7, wherein a gap
is interposed between the first magnetic component and the second
or third magnetic component provided separately from the first
magnetic component.
9. The coil antenna structure according to claim 3, wherein
cross-sectional areas of the second and the third magnetic
components are greater than a cross-sectional area of the first
magnetic component in a principal surface direction of the
casing.
10. The coil antenna structure according to claim 9, wherein the
second and the third magnetic components are substantially in the
shape of one of a sheet and a film.
11. The coil antenna structure according to claim 10, wherein the
first magnetic component is substantially in the shape of one of a
sheet and a film.
12. The coil antenna structure according to claim 1, wherein the
first magnetic component is disposed in the vicinity of an end
portion of the casing.
13. The coil antenna structure according to claim 1, wherein a
circuit substrate is disposed in the casing, the first magnetic
component is disposed so as to penetrate the circuit substrate, and
an incision portion extending in a direction farther from the first
magnetic component is disposed at least in a conductor of a portion
surrounding the first magnetic component of the circuit
substrate.
14. The coil antenna structure according to claim 1, wherein the
casing comprises an electrically conductive frame arranged to
accommodate a liquid crystal display panel, and the first magnetic
component is disposed outside a loop defined by the electrically
conductive frame.
15. The coil antenna structure according to claim 14, wherein a
constriction portion is provided on the outside of the electrically
conductive frame, and the first magnetic component is disposed in
the constriction portion.
16. The coil antenna structure according to claim 1, wherein a
magnetic barrier component arranged to restrict passage of magnetic
flux through a route different from the magnetic path including the
first magnetic component is disposed in the vicinity of the first
magnetic component.
17. The coil antenna structure according to claim 3, wherein a
magnetic barrier component arranged to restrict passage of magnetic
flux through a route different from the magnetic path including the
first magnetic component is disposed on at least one of opposed
surfaces of the second and the third magnetic components or in a
space sandwiched by the opposed surfaces.
18. The coil antenna structure according to claim 1, wherein the
casing defines a primary casing, a secondary casing for defining a
clamshell structure together with the primary casing is provided,
and the first magnetic component is disposed at a connection pivot
portion of the primary casing for connecting the secondary
casing.
19. The coil antenna structure according to claim 1, wherein the
casing defines a primary casing, a secondary casing capable of
being freely opened or closed relative to the primary casing is
provided, and a fourth magnetic component is disposed in the
secondary casing, the fourth magnetic component extending at least
in the thickness direction of the secondary casing, defining a
magnetic path from a first principal surface to a second principal
surface of the secondary casing, and being magnetically connected
to the first magnetic component while the secondary casing is
closed relative to the primary casing.
20. The coil antenna structure according to claim 19, wherein a
fifth magnetic component magnetically connected to the fourth
magnetic component is disposed on the first principal surface side
of the secondary casing, and a sixth magnetic component
magnetically connected to the fourth magnetic component is disposed
on the second principal surface side of the secondary casing.
21. The coil antenna structure according to claim 20, wherein the
fourth, the fifth, and the sixth magnetic components comprises an
integral magnetic component.
22. The coil antenna structure according to claim 21, wherein the
integral magnetic component is a sheet-shaped magnetic component
that is bent over the first principal surface and the second
principal surface of the secondary casing.
23. The coil antenna structure according to claim 20, wherein a
plurality of groups, each comprising the fourth, the fifth, and the
sixth magnetic components, are provided.
24. The coil antenna structure according to claim 20, wherein at
least one of the fifth magnetic component and the sixth magnetic
component is provided separately from the fourth magnetic
component.
25. The coil antenna structure according to claim 24, wherein a gap
is interposed between the fourth magnetic component and the fifth
or sixth magnetic component provided separately from the fourth
magnetic component.
26. The coil antenna structure according to claim 20, wherein
cross-sectional areas of the fifth and the sixth magnetic
components are greater than a cross-sectional area of the fourth
magnetic component in the principal surface direction of the
secondary casing.
27. The coil antenna structure according to claim 26, wherein the
fifth and the sixth magnetic components are substantially in the
shape of one of a sheet and a film.
28. The coil antenna structure according to claim 27, wherein the
fourth magnetic component is substantially in the shape of one of a
sheet and a film.
29. The coil antenna structure according to claim 19, wherein the
fourth magnetic component is disposed in the vicinity of an end
portion of the secondary casing.
30. The coil antenna structure according to claim 19, wherein a
circuit substrate is disposed in the secondary casing, the fourth
magnetic component is disposed so as to penetrate the circuit
substrate, and an incision portion extending in a direction farther
from the fourth magnetic component is disposed at least in a
conductor of a portion surrounding the fourth magnetic component of
the circuit substrate.
31. The coil antenna structure according to claim 19, wherein the
secondary casing comprises an electrically conductive frame
arranged to accommodate a liquid crystal display panel, and the
fourth magnetic component is disposed outside a loop defined by the
electrically conductive frame.
32. The coil antenna structure according to claim 31, wherein a
constriction portion is provided on the outside of the electrically
conductive frame, and the fourth magnetic component is disposed in
the constriction portion.
33. The coil antenna structure according to claim 19, wherein a
magnetic barrier component for restricting passage of magnetic flux
through a route different from the magnetic path including the
fourth magnetic component is disposed in the vicinity of the fourth
magnetic component.
34. The coil antenna structure according to claim 20, wherein a
magnetic barrier component for restricting passage of magnetic flux
through a route different from the magnetic path including the
fourth magnetic component is disposed on at least one of opposed
surfaces of the fifth and sixth magnetic components or in a space
sandwiched by the opposed surfaces.
35. The coil antenna structure according to claim 1, wherein the
casing comprises an electrically conductive frame arranged to
accommodate a liquid crystal display panel, the frame surrounding
the magnetic path, and a nonconductive portion is provided as a
portion of the electrically conductive frame.
36. A coil antenna structure comprising: a magnetic component
disposed such that a magnetic flux is passed so as to detour around
or penetrate a region having a relatively low magnetic
permeability; and a coil component surrounding the magnetic
component.
37. The coil antenna structure according to claim 36, wherein the
magnetic component defines a first magnetic component, a second
magnetic component magnetically connected to the first magnetic
component is disposed on at least one end side of the first
magnetic component, and a cross-sectional area of the second
magnetic component is greater than a cross-sectional area of the
first magnetic component in a direction that is substantially
perpendicular to an extension direction of the first magnetic
component.
38. A portable electronic apparatus comprising the coil antenna
structure according to claim 1.
39. A portable electronic apparatus comprising the coil antenna
structure according to claim 36.
Description
BACKGROUND OF THE INVENTION
Field of the Invention
[0001] The present invention relates to a coil antenna provided in
a portable electronic apparatus and a portable electronic apparatus
including the coil antenna.
BACKGROUND OF THE INVENTION
Field of the Invention
[0002] A non-contact IC card, which has been widely used in recent
years, is configured to communicate with a reader/writer while a
magnetic flux from the reader/writer passes through a planar coil
disposed in the card.
[0003] In a cellular phone or other suitable portable electronic
apparatus including a non-contact IC card chip, the above-described
planar coil is disposed in any one of the surfaces (in the vicinity
of the surface) of the casing of the cellular phone. Since a
circuit substrate including a ground electrode, a metal battery
case, and other components are disposed, it is difficult for a
magnetic flux to pass through the inside of the cellular phone.
Therefore, a problem occurs in that a communication distance is
reduced. Furthermore, there is a problem in that the sensitivity
varies depending on a directional orientation. For example,
communication may not be performed at all when a cellular phone is
held over a reader/writer while being turned upside down.
[0004] In Japanese Unexamined Patent Application Publication No.
2000-113142 (Patent Document 1), a configuration in which a
high-permeability magnetic material sheet is disposed between a
coil antenna and an object is disclosed.
[0005] The information storage device disclosed in the
above-described Patent Document 1 includes a sheet that is affixed
to an affixation surface of the object. Therefore, when the device
is applied to, for example, a cellular phone, it can be
incorporated into the cellular phone by being affixed to, for
example, a battery case of the cellular phone.
[0006] The above-described structure is effective against a
magnetic flux from one side of the casing. However, it is
ineffective against a magnetic flux from a side opposite thereto.
Consequently, the problem is not solved, and communication cannot
be performed when a cellular phone is disposed over a reader/writer
while being turned upside down.
SUMMARY OF THE INVENTION
[0007] In order to overcome the above-described problems, preferred
embodiments of the present invention provide a coil antenna device
capable of communicating even when a portable electronic apparatus
incorporating a non-contact IC card chip is held over a
reader/writer while being turned upside down and ensuring a
required amount of communication distance, and a portable
electronic apparatus provided with the device.
[0008] A coil antenna and a portable electronic apparatus according
to preferred embodiments of the present invention are described
below.
[0009] A coil antenna includes a tabular casing having a first
principal surface and a second principal surface opposed thereto
and includes a magnetic component and a coil component surrounding
the magnetic component in the casing, the magnetic component
extending at least in the thickness direction of the casing and
defining a magnetic path from the first principal surface side to
the second principal surface side.
[0010] Preferably, the coil antenna is configured such that the
above-described magnetic component defines a first magnetic
component, and a second magnetic component magnetically connected
to the first magnetic component is disposed on the first principal
surface side of the above-described casing.
[0011] Preferably, the coil antenna is configured such that a third
magnetic component magnetically connected to the first magnetic
component is disposed on the second principal surface side of the
above-described casing.
[0012] Preferably, the coil antenna is configured such that the
first, second, and third magnetic components are composed of an
integral magnetic component.
[0013] Preferably, the above-described integral magnetic component
is a sheet-shaped magnetic component bent over the first principal
surface and the second principal surface of the above-described
casing.
[0014] Preferably, the coil antenna is configured such that a
plurality of groups, each composed of the above-described first,
second, and third magnetic components, are provided.
[0015] Preferably, the coil antenna is configured such that at
least one of the second magnetic component and the third magnetic
component is provided separately from the first magnetic
component.
[0016] Preferably, the coil antenna is configured such that a gap
is interposed between the first magnetic component and the second
or the third magnetic component provided separately from the first
magnetic component.
[0017] Preferably, the coil antenna is configured such that the
cross-sectional areas of the second and the third magnetic
components are specified to be larger than the cross-sectional area
of the first magnetic component in the surface direction of the
above-described casing.
[0018] Preferably, the coil antenna structure is configured such
that the second and the third magnetic components are substantially
in the shape of a sheet or a film.
[0019] Preferably, the coil antenna is configured such that the
first magnetic component is substantially in the shape of a sheet
or a film.
[0020] Preferably, the coil antenna is configured such that the
first magnetic component is disposed in the vicinity of an end
portion of the above-described casing.
[0021] Preferably, a circuit substrate is disposed in the
above-described casing, the first magnetic component is disposed so
as to penetrate the circuit substrate, and an incision portion
extending in a direction farther from the first magnetic component
is disposed at least in a conductor of a portion surrounding the
first magnetic component of the circuit substrate.
[0022] Preferably, the above-described casing is provided with an
electrically conductive frame for a liquid crystal display panel,
and the above-described first magnetic component is disposed
outside a loop formed from the electrically conductive frame.
[0023] Preferably, a constriction portion is provided on the
outside of the above-described electrically conductive frame, and
the above-described first magnetic component is disposed in the
constriction portion.
[0024] Preferably, a magnetic barrier component for restricting
passage of the magnetic flux through a route different from the
above-described magnetic path including the above-described first
magnetic component is disposed in the vicinity of the
above-described first magnetic component.
[0025] Preferably, a magnetic barrier component for restricting
passage of the magnetic flux through a route that is different from
the above-described magnetic path including the above-described
first magnetic component is disposed on at least one of opposed
surfaces of the second and the third magnetic components or inside
the opposed surfaces.
[0026] Preferably, the coil antenna is configured such that the
above-described casing serves as a primary casing, a secondary
casing defining a clamshell structure together with the primary
casing is disposed, and the first magnetic component is disposed at
a connection pivot portion of the primary casing for connecting the
secondary casing.
[0027] Preferably, the coil antenna is configured such that the
above-described casing serves as a primary casing, a secondary
casing capable of being freely opened or closed relative to the
primary casing is provided, and a fourth magnetic component is
disposed in the secondary casing, the fourth magnetic component
extending at least in the thickness direction of the secondary
casing, defining a magnetic path from the first principal surface
to the second principal surface of the secondary casing, and being
magnetically connected to the first magnetic component while the
secondary casing is closed relative to the primary casing.
[0028] Preferably, the coil antenna is configured such that a fifth
magnetic component magnetically connected to the fourth magnetic
component is disposed on the first principal surface side of the
secondary casing, and a sixth magnetic component magnetically
connected to the fourth magnetic component is disposed on the
second principal surface side of the secondary casing.
[0029] Preferably, the coil antenna is configured such that the
fifth and the sixth magnetic components are integral with the
fourth magnetic component.
[0030] Preferably, the above-described integral magnetic component
is a sheet-shaped magnetic component bent over the first principal
surface and the second principal surface of the above-described
secondary casing.
[0031] Preferably, the coil antenna is configured such that a
plurality of groups, each composed of the above-described fourth,
the fifth, and the sixth magnetic components, are provided.
[0032] Preferably, the coil antenna is configured such that at
least one of the fifth magnetic component and the sixth magnetic
component is provided separately from the fourth magnetic
component.
[0033] Preferably, the coil antenna is configured such that a gap
is interposed between the fourth magnetic component and the fifth
or sixth magnetic component provided separately from the fourth
magnetic component.
[0034] Preferably, the coil antenna is configured such that the
cross-sectional areas of the fifth and the sixth magnetic
components are greater than the cross-sectional area of the fourth
magnetic component in the surface direction of the secondary
casing.
[0035] Preferably, the coil antenna is configured such that the
fifth and the sixth magnetic components are substantially in the
shape of a sheet or a film.
[0036] Preferably, the coil antenna is configured such that the
fourth magnetic component is substantially in the shape of a sheet
or a film.
[0037] Preferably, the coil antenna is configured such that the
fourth magnetic component is disposed in the vicinity of an end
portion of the secondary casing.
[0038] Preferably, a circuit substrate is disposed in the
above-described secondary casing, the fourth magnetic component is
disposed so as to penetrate the circuit substrate, and an incision
portion extending in a direction farther from the fourth magnetic
component is disposed at least in a conductor of a portion
surrounding the fourth magnetic component of the circuit
substrate.
[0039] Preferably, the above-described secondary casing is provided
with an electrically conductive frame for a liquid crystal display
panel, and the above-described fourth magnetic component is
disposed outside a loop formed from the electrically conductive
frame.
[0040] Preferably, a constriction portion is provided on the
outside of the above-described electrically conductive frame, and
the above-described fourth magnetic component is disposed in the
constriction portion.
[0041] Preferably, a magnetic barrier component for restricting
passage of the magnetic flux through a route different from the
above-described magnetic path including the above-described fourth
magnetic component is disposed in the vicinity of the fourth
magnetic component.
[0042] Preferably, a magnetic barrier component for restricting
passage of the magnetic flux through a route different from the
above-described magnetic path including the above-described fourth
magnetic component is disposed on at least one of opposed surfaces
of the above-described fifth and sixth magnetic components or in a
space sandwiched by the opposed surfaces.
[0043] Preferably, the above-described casing is provided with an
electrically conductive frame for a liquid crystal display panel,
the frame surrounding the above-described magnetic path, and a
nonconductive portion is disposed as a portion of the electrically
conductive frame.
[0044] A coil antenna according to another preferred embodiment is
configured to include a magnetic component disposed such that a
magnetic flux is passed so as to detour around or penetrate a
region having a relatively low magnetic permeability and a coil
component surrounding the magnetic component.
[0045] Preferably, the coil antenna is configured such that the
above-described magnetic component defines a first magnetic
component, a second magnetic component magnetically connected to
the first magnetic component is disposed on at least one end side
of the first magnetic component, and the cross-sectional area of
the second magnetic component is greater than the cross-sectional
area of the first magnetic component in a direction that is
substantially perpendicular to the extension direction of the first
magnetic component.
[0046] A portable electronic apparatus according preferred
embodiments of the present invention includes any one of the
above-described coil antenna structures.
[0047] A coil antenna according to a preferred embodiment includes
the magnetic component and the coil component surrounding the
magnetic component in the tabular casing, the magnetic component
extending in the thickness direction of the casing and defining the
magnetic path from the first principal surface to the second
principal surface. Consequently, the magnetic component defines the
magnetic path of a magnetic flux to pass from the first principal
surface to the second principal surface side or in a direction
opposite thereto, and the coil component is disposed in the
magnetic path, so that, for example, when a chip of a non-contact
IC card is connected to the coil antenna, communication can be
performed by holding the casing over a reader/writer, when either
the surface on the first principal surface side or the second
principal surface side is aimed at the reader/writer.
[0048] The second magnetic component magnetically connected to the
first magnetic component extending in the thickness direction of
the casing is disposed on the first principal surface side of the
casing. Consequently, the magnetic resistance of the magnetic path
is reduced, the convergence of the magnetic flux is improved, and
the flux density passing through the coil component is increased,
such that the communication distance from the reader/writer can be
increased.
[0049] The third magnetic component is magnetically connected to
the first magnetic component. Consequently, the convergence of a
magnetic flux on the first magnetic component is further
improved.
[0050] The second and the third magnetic components are integrated
together with, for example, the first magnetic component.
Consequently, leakage of a magnetic flux is prevented, and the
convergence of a magnetic flux on the first magnetic component is
improved.
[0051] The integral magnetic component includes the sheet-shaped
magnetic component bent over the first principal surface and the
second principal surface of the casing. Consequently, a magnetic
path is constructed in a limited space, and a portable electronic
apparatus is constructed without increasing the size of the
casing.
[0052] The plurality of groups, each composed of the first, second,
and third magnetic components, are disposed. Consequently, the
communication sensitivity and the stability thereof are
improved.
[0053] At least one of the second magnetic component and the third
magnetic component is provided separately from the first magnetic
component. Consequently, the incorporation into the casing is
easily performed.
[0054] A similar effect can be exerted by interposing the gap
between the first magnetic component and the second or third
magnetic component provided separately from the first magnetic
component.
[0055] The cross-sectional areas of the second and third magnetic
components in the surface direction of the casing are greater than
the cross-sectional area of the first magnetic component.
Consequently, the convergence of a magnetic flux on the first
magnetic component is effectively improved while the volume of the
first magnetic component surrounded by the coil component in the
casing is maintained small.
[0056] The second and third magnetic components are preferably
substantially in the shape of a sheet or a film. Consequently, the
volume occupied by the second and third magnetic components in the
casing is reduced, and the entire apparatus can be
miniaturized.
[0057] A miniaturization effect can be further enhanced by
configuring the first magnetic component to be substantially in the
shape of a sheet or a film.
[0058] The first magnetic component is disposed in the vicinity of
the end portion of the casing. Consequently, interference of the
substrate arrangement in the casing is prevented, and the space is
efficiently used.
[0059] The first magnetic component is disposed so as to penetrate
the circuit substrate in the casing, and an incision portion is
disposed in a portion surrounding the first magnetic component of
the circuit substrate. Consequently, a counter-electromotive force
caused by an eddy current generated in the circuit substrate when a
magnetic flux passes through the first magnetic component is
suppressed, and a reduction in effective magnetic permeability of
the first magnetic component is suppressed.
[0060] The above-described first magnetic component is disposed
outside the loop formed from the electrically conductive frame for
a liquid crystal display panel included in the above-described
casing. Consequently, no eddy current flows through the
electrically conductive frame when a magnetic flux passes through
the first magnetic component, such that no counter-electromotive
force caused by an eddy current is generated and a reduction in
effective magnetic permeability of the first magnetic component is
avoided.
[0061] The constriction portion is provided on the outside of the
electrically conductive frame for a liquid crystal display panel,
and the first magnetic component is disposed in the constriction
portion. Consequently, the first magnetic component can be disposed
outside the loop formed from the electrically conductive frame
without reducing the size of the electrically conductive frame.
[0062] The magnetic barrier component for restricting passage of
the magnetic flux through a route different from the magnetic path
including the first magnetic component is disposed in the vicinity
of the first magnetic component. Consequently, a magnetic flux
interlinking with the coil component is further converged.
[0063] The magnetic barrier component for restricting passage of
the magnetic flux through a route different from the magnetic path
including the first magnetic component is disposed on at least one
of the opposed surfaces of the second and third magnetic components
or in the space sandwiched by the opposed surfaces. Consequently, a
magnetic flux interlinking with the coil component is further
converged.
[0064] The first magnetic component is disposed at the connection
pivot portion for connecting the secondary casing to the primary
casing provided with the magnetic component and the coil component.
Consequently, interference by the secondary casing is
prevented.
[0065] In the structure including the primary casing and the
secondary casing capable of being freely opened or closed relative
to the primary casing, the fourth magnetic component defining the
magnetic path from the first principal surface to the second
principal surface of the secondary casing is disposed, and this
fourth magnetic component is magnetically connected to the first
magnetic component on the primary casing side. Consequently, the
magnetic path penetrating the primary casing and the secondary
casing is provided, and the function as the coil antenna is
performed even when the secondary casing is closed relative to the
primary casing.
[0066] The fifth and sixth magnetic components magnetically
connected to the fourth magnetic component are disposed on the
first and the second principal surfaces of the above-described
secondary casing. Consequently, the magnetic resistance of the
magnetic path in the secondary casing is reduced, and the
convergence of the magnetic flux is improved.
[0067] When the fifth and sixth magnetic components are formed
integrally together with the fourth magnetic component, the number
of components is reduced, and the leakage of magnetic flux is
further reduced.
[0068] The integral magnetic component is composed of the
sheet-shaped magnetic component bent over the first principal
surface and the second principal surface of the secondary casing.
Consequently, a magnetic path is constructed in a limited space,
and a portable electronic apparatus is constructed without
increasing the size of the casing.
[0069] The plurality of groups, each composed of the fourth, fifth,
and sixth magnetic components, are disposed. Consequently, the
communication sensitivity and the stability thereof are
improved.
[0070] At least one of the fifth magnetic component and the sixth
magnetic component is provided separately from the fourth magnetic
component. Consequently, the flexibility of arrangement of these
magnetic components in the secondary casing is easily
increased.
[0071] A similar effect is provided by interposing the gap between
the fourth magnetic component and the fifth or sixth magnetic
component provided separately from the fourth magnetic
component.
[0072] The cross-sectional areas of the fifth and sixth magnetic
components in the surface direction of the casing are greater than
the cross-sectional area of the fourth magnetic component.
Consequently, the volume of the fourth magnetic component included
in the inside of the secondary casing is reduced, and the entire
apparatus can be miniaturized.
[0073] The fifth and sixth magnetic components are substantially in
the shape of a sheet or a film. Consequently, the volume occupied
by the fifth and sixth magnetic components in the casing is
reduced, and the entire apparatus can be miniaturized.
[0074] A miniaturization effect can be further improved by
configuring the fourth magnetic component to be substantially in
the shape of a sheet or a film.
[0075] The fourth magnetic component is disposed in the vicinity of
the end portion of the casing. Consequently, interference of the
substrate arrangement in the casing is prevented, and the space is
efficiently used.
[0076] The fourth magnetic component is disposed so as to penetrate
the circuit substrate in the secondary casing, and the incision
portion is disposed in a portion surrounding the fourth magnetic
component of the circuit substrate. Consequently, a
counter-electromotive force caused by an eddy current generated in
the circuit substrate when a magnetic flux passes through the
fourth magnetic component is suppressed, and a reduction in
effective magnetic permeability of the fourth magnetic component is
suppressed.
[0077] The above-described fourth magnetic component is disposed
outside the loop formed from the electrically conductive frame for
a liquid crystal display panel included in the above-described
casing. Consequently, no eddy current flows through the
electrically conductive frame when a magnetic flux passes through
the first magnetic component, so that no counter-electromotive
force due to an eddy current is generated and a reduction in
effective magnetic permeability of the fourth magnetic component is
avoided.
[0078] The constriction portion is provided on the outside of the
electrically conductive frame for a liquid crystal display panel,
and the fourth magnetic component is disposed in the constriction
portion. Consequently, the fourth magnetic component is disposed
outside the loop formed from the electrically conductive frame
without reducing the size of the electrically conductive frame.
[0079] The magnetic barrier component for restricting passage of
the magnetic flux through a route different from the magnetic path
including the fourth magnetic component is disposed in the vicinity
of the fourth magnetic component. Consequently, a magnetic flux
interlinking with the coil component is further converged.
[0080] The magnetic barrier component for restricting passage of
the magnetic flux through a route different from the magnetic path
including the fourth magnetic component is disposed on at least one
of the opposed surfaces of the fifth and sixth magnetic components
or in the space sandwiched by the opposed surfaces. Consequently, a
magnetic flux interlinking with the coil component is further
converged.
[0081] The nonconductive portion is disposed as a portion of the
electrically conductive frame for a liquid crystal display panel,
the frame surrounding the magnetic path. Consequently, eddy current
is prevented from passing through the electrically conductive
frame, so that no counter-electromotive force is generated due to
an eddy current, and a reduction in effective magnetic permeability
of the first and/or the fourth magnetic component is avoided.
[0082] The magnetic component and the coil component surrounding
the magnetic component are disposed such that a magnetic flux is
passed so as to detour around or penetrate a region having a
relatively low magnetic permeability. Consequently, communication
can be performed by holding a portable electronic apparatus
provided with this coil antenna structure over a reader/writer to
communicate with a non-contact IC chip provided with a coil
antenna, when either the surface on the right side or the back side
is aimed at the reader/writer.
[0083] The second magnetic component magnetically connected to the
first magnetic component is disposed on at least one end side of
the first magnetic component, and the cross-sectional area of the
second magnetic component is greater than the cross-sectional area
of the first magnetic component in a direction that is
substantially perpendicular to the extension direction of the first
magnetic component. Consequently, the convergence of a magnetic
flux on the first magnetic component is effectively improved while
the volume of the first magnetic component surrounded by the coil
component in the casing is maintained small. Therefore, the entire
apparatus can be miniaturized.
[0084] According to the portable electronic apparatus of preferred
embodiments of the present invention, communication with a
reader/writer can be performed by holding a tabular casing over the
reader/writer, while any one of the surfaces thereof is aimed at
the reader/writer.
[0085] Other features, elements, steps, characteristics and
advantages of the present invention will become more apparent from
the following detailed description of preferred embodiments of the
present invention with reference to the attached drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0086] FIGS. 1A and 1B are diagrams showing a coil antenna
structure according to a first preferred embodiment of the present
invention.
[0087] FIGS. 2A-2C are diagrams showing the configuration of a
cellular phone provided with a coil antenna structure according to
a second preferred embodiment of the present invention.
[0088] FIGS. 3A and 3B are diagrams showing the configuration of a
cellular phone provided with a coil antenna structure according to
a third preferred embodiment of the present invention.
[0089] FIG. 4 is a diagram showing the configuration of a cellular
phone provided with a coil antenna structure according to a fourth
preferred embodiment of the present invention.
[0090] FIGS. 5A-5D are diagrams showing some states in which the
cellular phone according to the fourth preferred embodiment of the
present invention is disposed over a reader/writer.
[0091] FIG. 6 is a diagram showing the configuration of a cellular
phone provided with a coil antenna structure according to a fifth
preferred embodiment of the present invention.
[0092] FIG. 7 is a diagram showing the configuration of a cellular
phone provided with a coil antenna structure according to a sixth
preferred embodiment of the present invention.
[0093] FIG. 8 is a sectional view showing the configuration of the
cellular phone according to the sixth preferred embodiment of the
present invention.
[0094] FIGS. 9A and 9B are a partial plan view showing the
configuration of a substrate in the inside of the cellular phone
according to the sixth preferred embodiment of the present
invention.
[0095] FIG. 10 is a partial perspective view showing the
configuration of the inside of the cellular phone according to the
sixth preferred embodiment of the present invention.
[0096] FIG. 11 is a diagram showing the configuration of a cellular
phone according to a seventh preferred embodiment of the present
invention.
[0097] FIGS. 12A and 12B are diagrams showing the configuration of
a cellular phone according to an eighth preferred embodiment of the
present invention.
[0098] FIG. 13 is a sectional view showing the configuration of a
cellular phone according to a ninth preferred embodiment of the
present invention.
[0099] FIGS. 14A-14C are diagrams showing the configuration of a
cellular phone according to a tenth preferred embodiment of the
present invention.
[0100] FIG. 15 is a perspective view showing the configuration of a
magnetic component of the cellular phone according to the tenth
preferred embodiment of the present invention.
[0101] FIGS. 16A and 16B are sectional views showing the
configuration of a cellular phone according to an eleventh
preferred embodiment of the present invention.
[0102] FIGS. 17A and 17B are diagrams showing the configuration of
the cellular phone according to the eleventh preferred embodiment
of the present invention.
[0103] FIGS. 18A-18D are diagrams showing the configuration of a
coil antenna according to a twelfth preferred embodiment of the
present invention.
[0104] FIGS. 19A and 19B is a diagram showing the configuration of
a coil antenna according to a thirteenth preferred embodiment of
the present invention.
[0105] FIG. 20 is a diagram showing the configuration of a cellular
phone provided with a coil antenna structure according to a
fourteenth preferred embodiment of the present invention.
[0106] FIG. 21 is a plan view of a magnetic barrier component 37
disposed in a coil antenna according to a fifteenth preferred
embodiment of the present invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0107] A coil antenna according to a first preferred embodiment of
the present invention will be described with reference to FIG.
1.
[0108] FIGS. 1A and 1B are sectional views showing two types of
coil antennas. In an example shown in FIG. 1A, a conductor 10
having a predetermined thickness and extension in the surface
direction and exhibiting a relatively low magnetic permeability is
provided, and a first magnetic component 1 extending in the
thickness direction of the conductor 10 is disposed at an end
portion of the conductor 10. On a first principal surface (upper
surface in the drawing) side of the conductor 10, a second magnetic
component 2 is magnetically connected to the first magnetic
component 1. Furthermore, a third magnetic component 3 magnetically
connected to the first magnetic component 1 is disposed on a second
principal surface (lower surface in the drawing) side of the
conductor 10.
[0109] In this manner, the first magnetic component 1 is disposed
along the end portion of the conductor 10, and the second magnetic
component 2 and the third magnetic component 3 are disposed along
the surface directions of the first principal surface and the
second principal surface, respectively, of the conductor 10.
Consequently, the cross-sectional areas of the second magnetic
component 2 and the third magnetic component 3 are greater than the
cross-sectional area of the first magnetic component 1 with respect
to the surface directions of the first and the second principal
surfaces of the conductor 10.
[0110] Ferrite having a relative magnetic permeability of about 15
is used for each of the first magnetic component 1, the second
magnetic component 2, and the third magnetic component 3. A higher
relative magnetic permeability of at least about 10 is preferable.
It is more preferable that the relative magnetic permeability is
specified to be at least about 30. Where the magnetic component is
disposed in the vicinity of a receptacle of a cellular phone, an
eddy current may pass the magnetic component due to a current
during charging, and a loss may be produced. Therefore, it is
preferable that the material has a resistivity of at least about
10.sup.10 [.OMEGA.cm], and more preferably, at least about
10.sup.11 [.OMEGA.cm]
[0111] The first magnetic component 1 is provided with a coil
component 11 (pick up coil) in which a conductor is wound so as to
surround the first magnetic component 1. When a magnetic field is
applied upward from the bottom in the drawing, the magnetic flux
.phi. extends upward past a route of the third magnetic component
3.fwdarw.the first magnetic component 1.fwdarw.the second magnetic
component 2. At that time, since the second magnetic component 2
and the third magnetic component 3 extend along the surface
directions of the first and the second principal surfaces of the
conductor 10, the convergence of the magnetic flux is increased.
Consequently, the density of the magnetic flux passing the first
magnetic component 1 is increased.
[0112] Since the magnetic flux .phi. passes through the first
magnetic component provided with the coil component 11 so as to
detour around the conductor 10, as described above, when the
applied magnetic field is modulated, it can be transmitted as a
signal or an electric power from the coil component 11.
[0113] The above-described structure functions as a coil antenna
which establishes magnetic field connection when the surface on the
second magnetic component 2 side or the third magnetic component 3
side is simply disposed on a region suitable for directing a
magnetic field toward the thickness direction of the conductor 10.
Communication with a circuit of an external reader/writer or other
suitable device is possible when a transmitter signal passes the
coil component 11 by the action of a circuit connected to the coil
component 11.
[0114] For example, when a non-contact IC chip connected to the
coil component 11 is provided, the communication with a
reader/writer for a non-contact IC chip is possible by simply
disposing any one of the first principal surface or the second
principal surface of the conductor 10 over the reader/writer.
[0115] In an example shown in FIG. 1B, a conductor having a
predetermined thickness and extension in the surface direction and
exhibiting a relatively low magnetic permeability (a conductor 10)
is provided, and a first magnetic component 1 is disposed so as to
penetrate the inside of the conductor 10. A second magnetic
component 2 is disposed on a first principal surface (upper surface
in the drawing) side of the conductor 10 and a third magnetic
component 3 is disposed on a second principal surface (lower
surface in the drawing) side of the conductor 10 relative to this
first magnetic component 1, and the second and the third magnetic
components 2 and 3 are magnetically connected to the first magnetic
component 1.
[0116] The cross-sectional areas of the second magnetic component 2
and the third magnetic component 3 are greater than the
cross-sectional area of the first magnetic component 1 with respect
to the surface directions of the first and the second principal
surfaces of the conductor 10. That is, the first magnetic component
1 is disposed so as to penetrate a portion of the conductor 10, and
the second magnetic component 2 and the third magnetic component 3
are disposed so as to extend in the surface directions of the first
principal surface and the second principal surface, respectively,
of the conductor 10.
[0117] The first magnetic component 1 is provided with a coil
component 11 (pick up coil) in which a conductor is wound so as to
surround the first magnetic component 1. When a magnetic field is
applied upward from the bottom in the drawing, the magnetic flux
.phi. extends upward past a route of the third magnetic component
3.fwdarw.the first magnetic component 1.fwdarw.the second magnetic
component 2. At that time, since the second magnetic component 2
and the third magnetic component 3 extend along the surface
directions of the first and the second principal surfaces of the
conductor 10, the convergence of the magnetic flux is increased.
Consequently, the magnetic flux density passing the first magnetic
component 1 is increased and, in addition, a wider positional
relationship suitable for being in the state of being connected to
the antenna portion of the above-described reader/writer is
ensured.
[0118] In the examples shown in FIGS. 1A and 1B, each of the second
magnetic component 2 and the third magnetic component 3 is
magnetically connected to the first magnetic component 1. However,
among these, any one of the second and the third magnetic
components may be magnetically connected to the first magnetic
component 1. The first magnetic component 1 extending in the
thickness direction of the conductor 10 may be disposed alone. In
every case, the convergence of the magnetic flux is reduced.
However, miniaturization and cost reduction is facilitated because
the constituent factors are simplified.
[0119] A cellular phone according to a second preferred embodiment
will be described below with reference to FIGS. 2A-2C.
[0120] FIG. 2A is a sectional view of a portion of a cellular
phone. A casing 14 of the cellular phone 50 has a tabular shape. A
circuit substrate (hereafter simply referred to as a "substrate")
13 defining an electronic circuit is disposed in the inside of the
casing 14. A first magnetic component 1 is disposed at an end
portion of the casing 14. This first magnetic component 1 is
provided with a coil component 11 in which a conductor coil is
wound so as to surround a magnetic flux passing the first magnetic
component. A second magnetic component 2 magnetically connected to
the first magnetic component 1 is disposed on a first principal
surface (upper surface in the drawing) S1 side of the casing 14.
Furthermore, a third magnetic component 3 magnetically connected to
the first magnetic component 1 is disposed on a second principal
surface (lower surface in the drawing) S2 side of the casing 14.
The cross-sectional areas of the second magnetic component 2 and
the third magnetic component 3 are greater than the cross-sectional
area of the first magnetic component 1 with respect to the surface
direction of the casing 14 (the surface directions of the first and
the second principal surfaces of the substrate 13).
[0121] The above-described substrate 13 in the casing 14 extends to
the vicinity of the end portion thereof. Therefore, a magnetic path
composed of the first magnetic component 1, the second magnetic
component 2, and the third magnetic component 3 is disposed so as
to detour around the substrate 13.
[0122] When a magnetic field is applied upward from the bottom in
the drawing, the magnetic flux .phi. extends upward past a route of
the third magnetic component 3.fwdarw.the first magnetic component
1.fwdarw.the second magnetic component 2. Since the second magnetic
component 2 and the third magnetic component 3 extend along the
surface directions of the first and the second principal surfaces
of the casing 14, that is, the direction perpendicular to the
direction of the magnetic field, the convergence of the magnetic
flux is increased. Consequently, the magnetic flux density passing
the first magnetic component 1 is increased.
[0123] Furthermore, an antenna 12 for the cellular phone is
disposed at the end portion opposite to the end portion at which
the first magnetic component 1 of the casing 14 is disposed.
[0124] A non-contact IC chip is connected to the above-described
coil component 11. This non-contact IC chip, the coil component 11,
and the first to third magnetic components 1 to 3 define a data
carrier used for RFID (Radio Frequency Identification (non-contact
data identification technology)).
[0125] FIGS. 2B and 2C show the states in which the cellular phone
is disposed over a reader/writer of the RFID. In the state shown in
FIG. 2B, the surface (key control portion surface) of the cellular
phone is directed upward, and the back surface is aimed at the
reader/writer 100. Conversely, in the state shown in FIG. 2C, the
surface of the cellular phone is aimed at the reader/writer
100.
[0126] The reader/writer 100 radiates a magnetic flux such that a
magnetic field is directed in a direction perpendicular to the
surface (a surface over which the cellular phone is disposed)
thereof. Since a magnetic path composed of the first to the third
magnetic components 1 to 3 is disposed in the casing 14 of the
cellular phone 50, the magnetic flux .phi. radiates from the
reader/writer 100 passes the magnetic path and extends upward from
the upper surface of the casing 14. In an example shown in FIG. 2B,
the magnetic flux .phi. passes a route of the third magnetic
component 3.fwdarw.the first magnetic component 1.fwdarw.the second
magnetic component 2, and in an example shown in (C), the magnetic
flux .phi. passes a route of the second magnetic component 2
.fwdarw.the first magnetic component 1.fwdarw.the third magnetic
component 3.
[0127] Since magnetic lines of force form a closed loop, the
magnetic flux extending upward returns to the antenna portion of
the reader/writer 100 through the surroundings.
[0128] In this manner, the entire magnetic path including the first
magnetic component 1 wound with the coil component 11 has a
U-shape. Consequently, an electric power can be supplied to and
communication can be performed with the IC chip through the use of
electromagnetic induction due to the magnetic flux converged by the
second magnetic component 2 and the third magnetic component 3.
Therefore, it is possible to mutually communicate with the
reader/writer 100 regardless of whether the right side or back side
of the cellular phone 50 is disposed adjacent to the reader/writer
100.
[0129] A capacitor is connected to the above-described coil
component 11 so as to define a resonant circuit. The resonant
frequency thereof corresponds to the resonant frequency of an
electromagnetic wave transmitted from the reader/writer 100, and is
set at about 13.56 MHz, for example. The resonant circuit of the
non-contact IC chip receives an electromagnetic field from the
reader/writer 100 by a resonant operation of the above-described
resonant circuit, converts the received electromagnetic field to an
electric signal, and supplies the electric signal to the IC chip.
The IC chip performs writing to or reading from internal memory
and, thereafter, induces voltage variation on the reader/writer
side of an external apparatus through a switching operation by an
FET in the IC chip, so as to perform non-contact communication.
[0130] The above-described first to third magnetic components 1 to
3 may preferably be constructed by molding a mixed material of a
ferrite powder and a resin. Alternatively, they may be formed by
applying a ferrite resin paste to cellular phone inner wall
portions. When the first to third magnetic components 1 to 3 are
composed of the mixed material including the ferrite powder, as
described above, the impact resistance and the weight reduction of
the first to third magnetic components is achieved, and an antenna
can be configured to be resistant to breakage due to a drop of the
cellular phone. Since the first magnetic component 1 provided with
the coil component 11, on which a magnetic flux is concentrated,
has a small cross-sectional area, it is desirable that the magnetic
permeability is increased as compared with those of the second and
the third magnetic components by using a high magnetic permeability
ferrite powder, increasing the volume ratio of the ferrite powder,
or increasing the particle diameter of the ferrite powder.
Therefore, the first magnetic component may be easily composed of a
sintered magnetic material.
[0131] A cellular phone according to a third preferred embodiment
will be described below with reference to FIGS. 3A and 3B.
[0132] In this example, a so-called clamshell structure is
provided, in which a secondary casing 18 is connected to a primary
casing 17 with a connection pivot 19 so as to be freely opened or
closed. In this example, a first magnetic component 1 extending in
the thickness direction of the primary casing 17 is disposed in the
portion of the connection pivot 19 of the primary casing 17
connected to the secondary casing 18, and the first magnetic
component 1 is provided with a coil component 11. A second magnetic
component 2 magnetically connected to the first magnetic component
1 is disposed on the first principal surface (upper surface in FIG.
3A) side of the primary casing 17.
[0133] Furthermore, a third magnetic component 3 magnetically
connected to the first magnetic component 1 is disposed on the
second principal surface (lower surface in the drawing) side of the
primary casing 17.
[0134] FIG. 3A shows the state in which an upper surface is the
secondary casing 18 side and a lower surface is the primary casing
17 side. Conversely, FIG. 2B shows the state in which a lower
surface is the secondary casing 18 side and an upper surface is the
primary casing 17 side.
[0135] A reader/writer 100 radiates a magnetic flux such that a
magnetic field is directed in a direction perpendicular to the
surface (a surface over which the cellular phone is held) thereof.
This magnetic flux passes a magnetic path composed of the first to
the third magnetic components 1 to 3 of a cellular phone, and comes
upward. In the example shown in FIG. 3A, the magnetic flux .phi.
passes a route of the third magnetic component 3.fwdarw.the first
magnetic component 1.fwdarw.the second magnetic component 2, and in
the example shown in (B), the magnetic flux .phi. passes a route of
the second magnetic component 2.fwdarw.the first magnetic component
1 .fwdarw.the third magnetic component 3.
[0136] In this manner, the entire magnetic path including the first
magnetic component 1 wound with the coil component 11 has a
U-shape. Consequently, an electric power can be supplied to and
communication of signals can be performed with the IC chip through
the use of electromagnetic induction due to the magnetic flux
converged by the second magnetic component 2 and the third magnetic
component 3. Therefore, it is possible to communicate mutually with
the reader/writer 100 regardless of whether the right side or back
side of the cellular phone is disposed adjacent to the
reader/writer 100.
[0137] A cellular phone according to a fourth preferred embodiment
will be described below with reference to FIG. 4.
[0138] This cellular phone 50 also has a so-called clamshell
structure, in which a secondary casing 18 is connected to a
connection pivot 19 of a primary casing 17 so as to be freely
opened or closed. In the third preferred embodiment, the U-shaped
magnetic path composed of the first to the third magnetic
components is provided in the connection pivot portion thereof.
However, in the fourth preferred embodiment, a magnetic path is
provided in the end portions overlapping one another while the
secondary casing 18 is closed relative to the primary casing
17.
[0139] At the end portion of the primary casing 17, the second
magnetic component 2 is disposed in the first principal surface
(upper surface in the drawing) of the primary casing 17, and the
third magnetic component 3 is disposed in the second principal
surface (lower surface in the drawing) of the primary casing 17. At
the end portion of the secondary casing 18, a fourth magnetic
component 4, which is magnetically connected to the above-described
first magnetic component 1 while the secondary casing 18 is closed
relative to the primary casing 17, is disposed, a fifth magnetic
component 5 magnetically connected to the fourth magnetic component
4 is disposed on the first principal surface (upper surface in the
drawing) side of the secondary casing 18, and a sixth magnetic
component 6 magnetically connected to the fourth magnetic component
4 is disposed on the second principal surface (lower surface in the
drawing) side of the secondary casing 18.
[0140] The cross-sectional areas of the second magnetic component 2
and the third magnetic component 3 are greater than the
cross-sectional area of the first magnetic component 1 with respect
to the surface directions of the first and the second principal
surfaces of the primary casing 17. Likewise, the cross-sectional
areas of the fifth magnetic component 5 and the sixth magnetic
component 6 are greater than the cross-sectional area of the fourth
magnetic component 4 with respect to the surface directions of the
first and the second principal surfaces of the secondary casing
18.
[0141] The magnetic path composed of the first to the third
magnetic components 1 to 3 on the primary casing 17 side has a
U-shape and detours around an end portion of a substrate 15 in the
inside of the primary casing 17. Likewise, the magnetic path
composed of the fourth to the sixth magnetic components 4 to 6 on
the secondary casing 18 side has a U-shape and detours around an
end portion of a substrate 16 on the secondary casing 18 side.
[0142] As shown in FIG. 4, the above-described magnetic path on the
primary casing 17 side is magnetically connected to the
above-described magnetic path on the secondary casing 18 while the
secondary casing 18 is closed relative to the primary casing 17.
Consequently, as indicated by the magnetic flux .phi., the magnetic
flux passes through these magnetic paths in the thickness direction
of the casings (17 and 18), and a required amount of magnetic flux
density passing through the portion of the coil component 11 is
ensured.
[0143] FIGS. 5A-5D shows various states in which this cellular
phone is disposed over a reader/writer of RFID. In the state shown
in FIG. 5A, the primary casing 17 side is aimed at the
reader/writer 100 while the secondary casing 18 is closed relative
to the primary casing 17. Conversely, in the state shown in FIG.
5B, the secondary casing 18 side is aimed at the reader/writer 100
while the secondary casing 18 is closed relative to the primary
casing 17. In the state shown in FIG. 5C, a key control surface and
a liquid crystal panel surface are disposed over the reader/writer
100 while the secondary casing 18 is opened partway relative to the
primary casing 17. In the state shown in FIG. 5D, the back surface
side of the liquid crystal panel is disposed over the reader/writer
100 while the secondary casing 18 is opened partway relative to the
primary casing 17.
[0144] In the example shown in FIG. 5A, the magnetic flux .phi.
passes a route of the third magnetic component 3.fwdarw.the first
magnetic component 1.fwdarw.the second magnetic component
2.fwdarw.the sixth magnetic component 6.fwdarw.the fourth magnetic
component 4.fwdarw.the fifth magnetic component 5, and in the
example shown in FIG. 5B, the magnetic flux .phi. passes in a
direction opposite thereto. In each case, the magnetic flux .phi.
passes through the coil component disposed on the first magnetic
component 1.
[0145] In the example shown in FIG. 5C, the magnetic flux .phi.
passes a route of the second magnetic component 2.fwdarw.the first
magnetic component 1.fwdarw.the third magnetic component 3, and in
the example shown in FIG. 5D, the magnetic flux .phi. passes in a
direction opposite thereto. In each case, the magnetic flux .phi.
passes through the coil component disposed on the first magnetic
component 1.
[0146] In this manner, it is possible to communicate with the
reader/writer 100 even when the cellular phone is disposed over the
reader/writer 100 in various arrangements.
[0147] The configuration of a cellular phone according to a fifth
preferred embodiment will be described below with reference to FIG.
6.
[0148] FIG. 6 is a sectional view of a key portion thereof. In the
fourth preferred embodiment, each of the primary casing 17 and the
secondary casing 18 is provided with a U-shape magnetic path
directed in the same direction while the casing is closed. However,
in the fifth preferred embodiment, the directions of the U-shape
magnetic paths of the primary casing 17 and the secondary casing 18
are opposite to each other. A composite dielectric material antenna
22 is disposed between the U-shape magnetic path composed of first
to third magnetic components 1 to 3 of the primary casing 17. The
magnetic flux .phi. fo a reader/writer passes a route of the fifth
magnetic component 5.fwdarw.the fourth magnetic component
4.fwdarw.the sixth magnetic component 6.fwdarw.the second magnetic
component 2.fwdarw.the first magnetic component 1.fwdarw.the third
magnetic component 3 while the primary casing 17 and the secondary
casing 18 are closed. Both ends of a coil component 11 disposed on
the first magnetic component 1 are connected to a non-contact IC
chip 21.
[0149] Usually, the RFID and the cellular phone use frequencies
entirely different from each other and, therefore, they have almost
no sensitivity to the signal of the other. However, when the
communication is performed at point-blank range from the
reader/writer, the communication of the cellular phone may be
adversely affected by the reader/writer. The communication of the
cellular phone can be prevented from being adversely affected by
the reader/writer through the use of a composite dielectric
material antenna composed of, for example, a dielectric material
powder and a resin, as a main antenna for such a cellular phone, in
which the frequency is high and it is difficult to use a magnetic
material and disposition of the antenna so as to be surrounded by
the U-shape magnetic path composed of the magnetic components 1 to
3. That is, a strong electromagnetic field of the reader/writer is
applied to the cellular phone during the RFID communication.
However, the main antenna for the cellular phone is magnetically
shielded from the strong electromagnetic field of the reader/writer
by the above-described U-shape magnetic path. Therefore, the
electromagnetic field is prevented from entering the main antenna
used for the cellular phone. To achieve this effect, it is
preferable that the magnetic components 1 to 3 are formed from a
material having a large magnetic permeability in the vicinity of
the frequency to be used by the RFID and a small magnetic
permeability (relative magnetic permeability is about 1) in the
communication frequency band of the cellular phone.
[0150] A cellular phone according to a sixth preferred embodiment
will be described below with reference to FIG. 7 to FIG. 10.
[0151] This cellular phone has a so-called clamshell structure in
which a secondary casing 18 is connected to a connection pivot of a
primary casing 17 so as to be freely opened or closed. FIG. 7 is an
external view of a cellular phone in the state in which the
secondary casing is opened relative to the primary casing. FIG. 8
is a sectional view in the state in which the secondary casing 18
is closed relative to the primary casing 17. The connection pivot
is not shown in FIG. 8.
[0152] In the examples shown in the first to the fifth preferred
embodiments, the coil component 11 is wound in the close vicinity
of the first magnetic component 1. In the sixth preferred
embodiment, as shown in FIG. 7, a coil component 11 defining a loop
surface extending in the principal surface direction of the primary
casing 17 is provided. In this example, a battery pack 31 inside of
the primary casing 17 is included in the inside of the loop surface
formed by the above-described coil component 11. The secondary
casing 18 is provided with a liquid crystal display panel 32. For
the coil component 11, for example, a coil pattern including about
3 turns is provided on a polyimide film.
[0153] In the examples shown in the first to the fifth preferred
embodiments, the first magnetic component formed of sintered
ferrite is disposed outside the portion occupied by the substrate
in the casing. In the sixth preferred embodiment, as shown in FIG.
8, the first magnetic component 1 penetrates a substrate 15 at a
predetermined location. The second and the third magnetic
components 2 and 3 are composed of magnetic sheets extending in the
principal surface direction of the primary casing 17, and are
disposed in the vicinity of the lower surface and in the vicinity
of the upper surface, respectively, of the primary casing 17 so as
to sandwich the first magnetic component 1. In the secondary casing
18, a substrate 16, and liquid crystal display panels 32 and 33,
are provided and, in addition, a fourth magnetic component 4 formed
of a ferrite composite material is disposed at a location in the
vicinity of an end portion of the substrate 16 so as not to
penetrate the substrate 16.
[0154] Furthermore, magnetic components 5 and 6 composed of
magnetic sheets are disposed so as to sandwich this fourth magnetic
component 4.
[0155] The relative magnetic permeability of the above-described
ferrite composite material is about 10, and the relative magnetic
permeability of the above-described sintered ferrite is about 70 at
a frequency to be used by the RFID of about 13.56 MHz.
[0156] As described above, the substrate 15 on the primary casing
17 side tends to be larger than the substrate 16 on the secondary
casing 18 side. If the first magnetic component 1 is disposed so as
to penetrate the substrate 15, the following problems occur.
[0157] Since an electrode pattern (in particular, a ground
electrode) is disposed on the substrate 15, if a magnetic flux
penetrates the electrode pattern, an induced current (eddy current)
is generated in the electrode pattern. FIG. 9A shows the state
thereof. When a ground electrode is disposed on the substrate 15,
if an alternating magnetic flux .phi. passes the first magnetic
component 1, an eddy current Is flows due to electromagnetic
induction. The effective magnetic permeability of the first
magnetic component 1 formed from ferrite is reduced by a
counter-electromotive force caused by the eddy current.
[0158] Consequently, as shown in FIG. 9B, an incision portion S
extending in a direction farther from the first magnetic component
1 is disposed in the electrode pattern (ground electrode) of a
portion surrounding the first magnetic component 1 of the substrate
15.
[0159] FIG. 10 is a partial plan view of the substrate 15 provided
with the incision portion S. The eddy current Is generated by the
magnetic flux passing the first magnetic component 1 tends to flow
around the first magnetic component 1. However, since the incision
portion S is disposed as described above, the flow route of the
eddy current Is in the vicinity of the first magnetic component is
cut. As a result, generation of the counter-electromotive force
caused by the eddy current Is is suppressed, and reduction of the
effective magnetic permeability of the first magnetic component 1
is suppressed.
[0160] It is essential only that the above-described incision
portion S is disposed in the electrode pattern. However, the
incision portion may be disposed in the entire substrate 15.
[0161] The above-described first magnetic component 1 is formed by,
for example, integrally disposing a composite material (ferrite
composite material) including a ferrite powder and a resin around
(side portion) a cylindrical sintered ferrite. Since the composite
material is disposed around the sintered body, as described above,
the magnetic resistance of the magnetic path is reduced and, in
addition, high impact resistance is achieved. Therefore, even when
a strong impact is imposed on the cellular phone due to drop or
other external force, breakage of the first magnetic component is
prevented. The same is true for the fourth magnetic component.
[0162] In the example shown in FIG. 8 and FIGS. 9A and 9B, the
first magnetic component 1 penetrates the substrate 15 on the
primary casing 17 side. However, the same can be applied in the
case where the fourth magnetic component 4 penetrates the substrate
16 on the secondary casing 18 side. In that case, it is recommended
that the substrate 16 is provided with an incision portion for
suppressing an eddy current.
[0163] A cellular phone according to a seventh preferred embodiment
will be described below with reference to FIG. 11.
[0164] In FIG. 11, the configuration of the inside of the primary
casing 17 and the secondary casing 18 are substantially the same as
those in the sixth preferred embodiment shown in FIG. 8. In FIG.
11, the primary casing 17 is provided with a coil component 11
similar to that in the cellular phone shown in the sixth preferred
embodiment. The secondary casing 18 is provided with a liquid
crystal display panel 32. In order to suppress unnecessary emission
of a harmonic noise generated in the dynamic driving of a large and
high-resolution liquid crystal display panel, an electrically
conductive frame 34 made of an aluminum alloy, magnesium amalgam,
or other suitable material is disposed around the liquid crystal
display panel 32 in the secondary casing 18 to be provided with
this liquid crystal display panel 32.
[0165] Such an electrically conductive frame defines a loop defined
by an electrically conductive component. Therefore, in the state in
which the secondary casing is closed relative to the primary casing
17, a magnetic flux penetrating the coil component 11 also passes
in the loop of the above-described electrically conductive frame
34, and an induced current is generated in the electrically
conductive frame 34 due to the magnetic flux, so that a
counter-electromotive force is generated. As a result, the
effective magnetic permeability of a magnetic path composed of the
magnetic components 1, 2, and 3 disposed on the primary casing 17
side and the magnetic components 4, 5, and 6 disposed on the
secondary casing 18 side is reduced.
[0166] Consequently, in order that the electrically conductive
frame 34 does not define a loop, as shown in FIG. 11, nonconductive
portions 35 are disposed at midpoints thereof. In this manner, the
above-described induced current does not flow through the
electrically conductive frame 34, and reduction of the effective
magnetic permeability of the above-described magnetic path is
prevented.
[0167] A cellular phone according to an eighth preferred embodiment
will be described below with reference to FIGS. 12A and 12B.
[0168] In the example shown in FIG. 11, when the fourth magnetic
component is disposed in the secondary casing 18, the nonconductive
portions 35 are disposed in the electrically conductive frame 34
and, thereafter, the fourth magnetic component is disposed in the
nonconductive portions 35. In an example shown in the eighth
preferred embodiment, the fourth magnetic component 4 is disposed
outside the loop defined by the electrically conductive frame
34.
[0169] In an example shown in FIG. 12A, a magnetic component 4 is
disposed in the vicinity of an end portion of a secondary casing
18. In an example shown in FIG. 12B, a magnetic component 4 is
disposed in the vicinity of an electrically conductive frame 34. In
addition, in order that the electrically conductive frame 34
disposed in the inside of the secondary casing 18 is as wide as
possible, a constriction portion C is provided in a portion of the
electrically conductive frame 34 and, thereby, structural
interference with the fourth magnetic component 4 is prevented.
[0170] In the above-described structure, the electrically
conductive frame 34 provides an electrical loop and, therefore, the
effect of suppressing unnecessary emission of a harmonic noise
generated in the dynamic driving of a liquid crystal display panel
is maintained.
[0171] A cellular phone according to a ninth preferred embodiment
will be described below with reference to FIG. 13.
[0172] FIG. 13 is a sectional view of a section including both a
primary casing 17 and a secondary casing 8 in the state in which
the secondary casing 18 is closed relative to the primary casing
17. A substrate 15, a battery pack 31, and a coil component 11 are
disposed in the inside of the primary casing 17 and, in addition, a
magnetic material sheet 123 is disposed inside the loop defined by
the coil component 11. This magnetic material sheet 123 is composed
of an integral magnetic material sheet continuously extending from
the bottom surface of the primary casing 17, through end surfaces
of the battery pack 31 and the substrate 15, to the upper surface
of the substrate 15.
[0173] A liquid crystal display panel 32 and an electrically
conductive frame 34 are disposed in the secondary casing 18 and, in
addition, a magnetic material sheet 456 is continuously disposed
from one surface of the liquid crystal display panel 32, through an
end surface, to the other surface so as to define a magnetic path
outside the electrically conductive frame 34. This magnetic
material sheet 456 is composed of an integral magnetic material
sheet continuously extending from one surface of the secondary
casing 18, through end surfaces of the electrically conductive
frame 34 and the liquid crystal display panel 32, to the other
surface of the secondary casing 18.
[0174] With the above-described structure, a magnetic path having a
route, in which the magnetic flux passes in the loop defined by the
coil component 11 and the magnetic flux does not pass the loop
defined by the electrically conductive frame 34, is composed of two
magnetic material sheets 123 and 456 in the state in which the
secondary casing 18 is closed relative to the primary casing
17.
[0175] When the above-described magnetic material sheets 123 and
456 are provided, a magnetic path is provided in a limited amount
of space in the casing, and a required amount of magnetic flux
density passing through the coil component 11 is ensured without
increasing the size of the apparatus.
[0176] A cellular phone according to a tenth preferred embodiment
will be described below with reference to FIGS. 14A-14C and FIG.
15.
[0177] FIGS. 14A and 14B show the relationship between a magnetic
path composed of first to third magnetic components 1 to 3 and a
reader/writer antenna 41. In the case where the magnetic
permeability of the first magnetic component 1 formed from
cylindrical ferrite is not adequately high, as shown in FIG. 14A, a
magnetic path, in which a magnetic flux.phi. introduced from the
reader/writer 41 to the first magnetic component 1 is returned to
the reader/writer antenna 41 before passing the coil component 11,
is provided. Even in the case where the magnetic permeability of
the first magnetic component 1 is adequately high, a similar
phenomenon occurs depending on the magnetic resistance of a route
in which the magnetic flux passed through the first magnetic
component 1 passes air and returns to the reader/writer antenna
41.
[0178] Consequently, as shown in FIG. 14B, a magnetic barrier
component 36 for suppressing the passage of a magnetic flux is
disposed in a route in which a magnetic flux does not pass the coil
component 11 and returns to the reader/writer antenna 41. It is
recommended that a conductor is used as this magnetic barrier
component 36. For example, metal foil, e.g., a copper foil tape,
metal thin plates, e.g., a copper piece, and metal meshes, e.g., a
copper mesh, may be used.
[0179] FIG. 14C is a plan view showing the positional relationship
between the first magnetic component 1 and the magnetic barrier
component 36. In this manner, the magnetic barrier component 36 is
disposed in directions opposite to extension directions of the
second and the third magnetic components from the first magnetic
component at a location (inner surface of the casing) a
predetermined distance from the first magnetic component 1. With
this structure, the route of a magnetic flux, which does not pass
the coil component 11 and tends to take a shortcut, is interrupted
and magnetic flux leakage is prevented. The above-described
magnetic barrier component 36 may be affixed to the first magnetic
component 1.
[0180] FIG. 15 is a diagram showing an example of another
configuration of the magnetic barrier. In this example, a composite
material 1b composed of a ferrite powder and a resin is disposed
around sintered ferrite 1a, and a magnetic barrier component 36'
formed from a plating film through electroless copper plating is
disposed on the side surface of this composite material 1b. The
copper plating film formed on the side surface of the first
magnetic component 1, as described above, functions as the magnetic
barrier component. If the magnetic barrier component 36' is formed
entirely around the side surface of the cylindrical first magnetic
component 1, the above-described induced current problem occurs.
Therefore, the magnetic barrier component 36' is formed at a
location except for the portion indicated by a slit line SL such
that the magnetic barrier component 36' does not form a loop.
[0181] In this example, the composite material 1b is provided.
However, a film-shaped magnetic barrier component 36' may be formed
by performing copper plating directly on the side surface of the
cylindrical sintered ferrite or by baking a copper paste in which a
copper powder is dispersed in a vehicle.
[0182] The copper plating film or the baked film of the copper
paste defining the magnetic barrier may not always be formed into a
continuous film over the entire surface, but may be formed into a
predetermined pattern, e.g., a mesh pattern.
[0183] A cellular phone according to an eleventh preferred
embodiment will be described below with reference to FIGS. 16A and
16B and FIG. 17.
[0184] FIGS. 16A and 16B show the relationship between a magnetic
path composed of first to third magnetic components 1 to 3 and a
reader/writer antenna 41.
[0185] In order that the sensitivity is improved by collecting the
magnetic flux .phi. of the reader/writer antenna 41 and
communication is enabled with respect to various arrangements and
locations of the casing of the cellular phone, it is necessary to
use the second and the third magnetic components 2 and 3 having
specific areas. However, if the areas of the second and the third
magnetic components 2 and 3 formed from magnetic sheets or other
suitable materials are too large, as shown in FIG. 16A, a magnetic
path, in which a magnetic flux successfully captured by the third
magnetic component 3 returns directly to the reader/writer antenna
41 without passing the coil component 11, is produced. Likewise, in
the case where the second magnetic component 2 is aimed at the
reader/writer antenna 41, a magnetic flux captured by the second
magnetic component 2 also returns directly to the reader/writer
antenna 41 without passing the coil component 11.
[0186] Conversely, if the areas of the second and the third
magnetic components 2 and 3 are too small, the convergence of the
magnetic flux is reduced, and problems occur in that a magnetic
flux passing through the coil component 11 is reduced, or the
sensitivity greatly varies depending on the positional relationship
between the reader/writer antenna 41 and the casing.
[0187] When the size of the second and the third magnetic
components 2 and 3 are appropriate, as shown in FIG. 16B, the
magnetic flux passes through the coil component 11 and, thereby,
adequate communication sensitivity is ensured.
[0188] As described above, there is a tradeoff relationship between
the areas of the second and the third magnetic components 2 and 3
and the communication sensitivity and the stability thereof.
[0189] Therefore, in the eleventh preferred embodiment, the
magnetic component is divided in order to ensure the communication
sensitivity and reduce variations in communication sensitivity due
to the positional relationship between the reader/writer antenna 41
and the casing.
[0190] FIGS. 17A and 17B show a specific example thereof. As shown
in FIG. 17A, four magnetic paths are defined in a loop of the coil
component 11. Each magnetic path is composed of a first magnetic
component formed from cylindrical sintered ferrite and second and
third magnetic components formed from magnetic material sheets. In
FIG. 17A, the second magnetic component composed of rectangular
magnetic material sheets 123a, 123b, 123c, and 123d are shown. The
third magnetic component is also composed of a magnetic material
sheet in the same shape as that of the second magnetic component.
In this FIG. 17A, the first magnetic components formed from
cylindrical sintered ferrite are shown as circles indicated by
broken lines.
[0191] The area (area determined from a plan view) of each magnetic
material sheet defining the second or the third magnetic component
is specified to be a size which enables the magnetic flux from the
reader/writer antenna 41 to effectively pass the coil component,
and a plurality of magnetic components having the above-described
size are disposed while the number thereof is adequate for filling
in the loop formed by the coil component 11. With this structure,
the communication sensitivity is ensured and, in addition, the
sensitivity variation due to position change of the cellular phone
relative to the reader/writer antenna 41 maintained at a low
level.
[0192] In the example shown in FIGS. 17A and 17B, the first
magnetic component is constructed separately from the second and
the third magnetic components. However, the first to the third
magnetic components may be composed of an integral magnetic
material sheet. In such a case, each magnetic material sheet is
bent at the end portion of the substrate 15 so as to have a
U-shape.
[0193] A coil antenna according to a twelfth preferred embodiment
will be described below with reference to FIGS. 18A to FIG. 21.
[0194] FIGS. 18A-18D are diagrams showing the configuration of
first to third magnetic components and a magnetic barrier
component.
[0195] FIG. 18A is a perspective view showing the configuration of
the first to third magnetic components, and FIG. 18B is a front
view thereof. In this example, the first magnetic component 1 is
composed of a U-shaped ferrite core having a relative magnetic
permeability of about 70. The second and the third magnetic
components 2 and 3 are composite materials including a ferrite
powder and a resin material and are composed of a ferrite sheet
having a size of about 36.times.36 mm, a thickness of about 0.6 mm,
and a relative magnetic permeability of about 20 to about 50. The
first magnetic component 1 is wound with a coil 11.
[0196] FIG. 18C is a front view of the state in which magnetic
barrier components 37 are disposed relative to a magnetic path
composed of the first to the third magnetic components 1 to 3 shown
in FIGS. 18A and 18B. FIG. 18D is a plan view of the third magnetic
component provided with the magnetic barrier component 37. These
magnetic barrier components 37 are made of a copper (Cu) tape, and
are affixed to the second and the third magnetic components 2 and
3. This magnetic barrier component 37 is provided with an opening
portion H in the center portion of one of the sides thereof, and is
disposed so as to avoid positions at which the first magnetic
component 1 is in contact with the second and the third magnetic
components 2 and 3 and not to surround the perimeter of the first
magnetic component 1.
[0197] Likewise, the magnetic barrier component 37 is also disposed
relative to the second magnetic component 2.
[0198] In the case where the above-described magnetic barrier
component 37 is not disposed, as shown in FIG. 18B, in addition to
a magnetic flux .phi., which returns to the reader/writer antenna
41 through the third magnetic component 3.fwdarw.the first magnetic
component 1.fwdarw.the second magnetic component 2, a magnetic flux
.phi.v, which returns to the reader/writer antenna 41 through the
third magnetic component 3.fwdarw.the second magnetic component 2
(that is, not passing the first magnetic component 1) is
generated.
[0199] On the other hand, as shown in FIG. 18C, when the magnetic
barrier components 37 relative to the second and the third magnetic
components 2 and 3 are disposed on the opposed surfaces of these
second and the third magnetic components 2 and 3, the route of the
magnetic flux .phi.v, which tends to return to the reader/writer
antenna 41 from the third magnetic component 3 through the second
magnetic component 2, is substantially eliminated, and the magnetic
flux density of the fundamental route, which returns to the
reader/writer antenna 41 through the third magnetic component
3.fwdarw.the first magnetic component 1.fwdarw.the second magnetic
component 2, is increased.
[0200] For the configuration shown in FIG. 18B and the
configuration shown in FIG. 18C, the value of inductance was
adjusted such that the resonant frequency of the antenna is about
13.56 MHz, which was the frequency to be used, and a communicatable
distance from the reader/writer antenna was measured. As a result,
with the configuration shown in FIG. 18B, in which the magnetic
barrier component was not provided, the communicable distance was
about 131 mm, whereas with the configuration as shown in FIG. 18C,
in which the magnetic barrier component 37 was provided, the
communicable distance was about 149 mm. In this manner, the
communication distance is increased by affixing the magnetic
barrier components 37 to the second and the third magnetic
components 2 and 3.
[0201] A coil antenna according to a thirteenth preferred
embodiment will be described below with reference to FIGS. 19A and
19B.
[0202] FIG. 19A is a front view of a coil antenna, and FIG. 19B is
a plan view of a substrate disposed in the cellular phone together
with the coil antenna. This coil antenna is provided with first to
third magnetic components 1 to 3 and magnetic barrier components 37
affixed to the inner surface of the second and the third magnetic
components, as in the twelfth preferred embodiment shown in FIGS.
18A-18D. Furthermore, a substrate 15 is inserted at a location
sandwiched between the second and the third magnetic components 2
and 3 together with the magnetic barrier components 37.
[0203] As shown in FIG. 19B, a notch portion N is provided at the
center portion of one side of the substrate 15, and the first
magnetic component 1 is disposed in this notch portion N. Magnetic
barrier components 38 formed from copper (Cu) plating films are
disposed on both surfaces of this substrate 15. However, the
magnetic barrier components 38 are formed so that the entire
perimeter of the first magnetic component 1 is not surrounded by
the magnetic barrier components 38. Here, the substrate 15 has a
size of about 50.times.80 mm and a thickness of about 1.6 mm.
[0204] The communication distance was further increased from the
above-described 149 mm to about 161 mm by inserting the substrate
15 provided with the magnetic barrier components 38, as described
above. Furthermore, this value is a value in the state in which the
resonant frequency is deviated due to insertion of the substrate
15. Therefore, it is predicted that the communication distance will
be further increased by adjusting the inductance such that the
resonant frequency approaches about 13.56 MHz, which is the
frequency to be used.
[0205] As described above, the magnetic barrier component exerts an
effect even when being disposed at a location separated from the
magnetic component serving as a magnetic flux concentration
surface. Therefore, in FIGS. 19A and 19B, a configuration, in which
the magnetic barrier component 37 is not disposed, may be
adopted.
[0206] The magnetic barrier components 38 disposed on both surfaces
of the substrate 15 may be formed by affixing metal tapes or metal
foil, printing and applying an electrically conductive paste, or
other suitable methods instead of plating.
[0207] A cellular phone including a coil antenna according to a
fourteenth preferred embodiment will be described below with
reference to FIG. 20.
[0208] FIG. 20 is a sectional view of a cellular phone. In this
example, a first magnetic component 1 and a third magnetic
component 3 are disposed inside of a primary casing 17. (A second
magnetic component is not present in this example.) A magnetic
barrier component 37 similar to that shown in FIGS. 18A-18D is
disposed on the inner surface (a secondary casing 18 side) of the
third magnetic component 3.
[0209] Fourth to sixth magnetic components 4 to 6 are disposed
inside of the secondary casing 18. Magnetic barrier components 37
are disposed on opposed inner surfaces of the fifth and the sixth
magnetic components 5 and 6. The fourth magnetic component 4 is
wound with a coil component 11.
[0210] Each of the magnetic barrier components 37 disposed on the
magnetic components 3, 5, and 6 is formed from a copper (Cu)
tape.
[0211] When a cellular phone having a clamshell structure, as
described above, is moved close to an antenna of a reader/writer
while the primary casing 17 and the secondary casing 18 are closed,
the third magnetic component 3 defines a magnetic flux
concentration surface on the primary casing 17 side. The route of a
magnetic flux, which does not pass the fourth magnetic component 4
provided with the coil component 11 and returns to the
reader/writer antenna 41, is interrupted by disposing the magnetic
barrier component 37 on this third magnetic component 3.
Consequently, the magnetic flux density passing the coil component
11 is increased correspondingly.
[0212] A coil antenna structure according to a fifteenth preferred
embodiment will be described below with reference to FIG. 21.
[0213] FIG. 21 is a plan view of a magnetic barrier component. This
magnetic barrier component 37 is, for example, the magnetic barrier
component 37 shown in FIG. 18C, FIG. 19A, or FIG. 20. In the
example shown in FIG. 18D, the magnetic barrier components 37 are
disposed substantially over the entire surfaces of the magnetic
components 2 and 3. However, the magnetic barrier component present
in the vicinity of a region, through which the magnetic flux of the
reader/writer antenna passes (for example, the first magnetic
component 1), acts as a magnetic barrier, and the magnetic barrier
is reduced with decreasing proximity thereto. Therefore, in the
example shown in FIG. 21, a substantially semicircular portion
having a predetermined radius centering the first magnetic
component 1 is considered as a valid region Av, and a portion
outside it (a portion indicated by hatching) is considered as an
invalid region Ai. Therefore, the magnetic barrier component 37 may
not be disposed in regions W1 and W2, which are almost included in
the invalid region Ai, and these regions may be used for other
purposes.
[0214] While preferred embodiments of the present invention have
been described above, it is to be understood that variations and
modifications will be apparent to those skilled in the art without
departing the scope and spirit of the present invention. The scope
of the present invention, therefore, is to be determined solely by
the following claims.
* * * * *